TY - JOUR
T1 - Light exposure at night and sleep quality in bipolar disorder
T2 - The APPLE cohort study
AU - Esaki, Yuichi
AU - Kitajima, Tsuyoshi
AU - Obayashi, Kenji
AU - Saeki, Keigo
AU - Fujita, Kiyoshi
AU - Iwata, Nakao
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Background: Sleep disturbance in bipolar disorder (BD) is common and is associated with a risk for mood episode recurrence. Thus, it is important to identify factors that are related to sleep disturbance in BD. This cross-sectional study investigated the association between exposure to light at night (LAN) and sleep parameters in patients with BD. Methods: The sleep parameters of 175 outpatients with BD were recorded using actigraphy at their homes for seven consecutive nights and were evaluated using the Insomnia Severity Index (ISI). The average LAN intensity in the bedroom during bedtime and rising time was measured using a portable photometer, and the participants were divided into two groups: “Light” (≥5 lx) and “Dark” (<5 lx). The association between LAN and sleep parameters was tested with multivariable analysis by adjusting for potential confounder such as age, gender, current smoker, mood state, day length, daytime light exposure, and sedative medications. Results: After adjusting for potential confounder, the actigraphy sleep parameters showed significantly lower sleep efficiency (mean, 80.1%vs. 83.4%; p = 0.01), longer log-transformed sleep onset latency (2.9 vs. 2.6 min; p = 0.01), and greater wake after sleep onset (51.4 vs. 41.6 min; p = 0.02) in the Light group than in the Dark group. Whereas, there were no significant differences in the ISI scores between the groups. Limitations: This was a cross-sectional study; therefore, the results do not necessarily imply that LAN causes sleep disturbance. Conclusions: Reducing LAN exposure may contribute to improved sleep quality in patients with BD.
AB - Background: Sleep disturbance in bipolar disorder (BD) is common and is associated with a risk for mood episode recurrence. Thus, it is important to identify factors that are related to sleep disturbance in BD. This cross-sectional study investigated the association between exposure to light at night (LAN) and sleep parameters in patients with BD. Methods: The sleep parameters of 175 outpatients with BD were recorded using actigraphy at their homes for seven consecutive nights and were evaluated using the Insomnia Severity Index (ISI). The average LAN intensity in the bedroom during bedtime and rising time was measured using a portable photometer, and the participants were divided into two groups: “Light” (≥5 lx) and “Dark” (<5 lx). The association between LAN and sleep parameters was tested with multivariable analysis by adjusting for potential confounder such as age, gender, current smoker, mood state, day length, daytime light exposure, and sedative medications. Results: After adjusting for potential confounder, the actigraphy sleep parameters showed significantly lower sleep efficiency (mean, 80.1%vs. 83.4%; p = 0.01), longer log-transformed sleep onset latency (2.9 vs. 2.6 min; p = 0.01), and greater wake after sleep onset (51.4 vs. 41.6 min; p = 0.02) in the Light group than in the Dark group. Whereas, there were no significant differences in the ISI scores between the groups. Limitations: This was a cross-sectional study; therefore, the results do not necessarily imply that LAN causes sleep disturbance. Conclusions: Reducing LAN exposure may contribute to improved sleep quality in patients with BD.
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U2 - 10.1016/j.jad.2019.07.031
DO - 10.1016/j.jad.2019.07.031
M3 - Article
C2 - 31302520
AN - SCOPUS:85068582097
SN - 0165-0327
VL - 257
SP - 314
EP - 320
JO - Journal of Affective Disorders
JF - Journal of Affective Disorders
ER -